The production of three-dimensional farinaceous-based food products using an extruder and rotating knives of different lengths is disclosed in U.S. Pat. No. 4,802,838 to Schaaf, Japanese Laid-Open Patent No. 61-274673 (published Dec. 4, 1986), and Japanese Laid-Open Patent No. 61-280260 published Dec. 10, 1986 both to Hoki and assigned to Ohyama Foods Machinery Co., Ltd. A short knife is used to partially cut or make grooves in the extrudate as it exits the extruder. A long knife fully cuts the partially cut extrudate into pieces. However, all of the knives cut the extrudate from only a single die orifice.
To increase production rates of the individual pieces, the extrusion rate through the single orifice must be increased together with an increase in speed of rotation of the long and short knives. However, as these rates increase, cutting accuracy tends to decrease, and the pieces tend to get thrown with greater force which can result in excessive deformation or damage to the pieces. Production rates may be increased by adding more single orifice extruders to the production line. However, the cost involved in using multiple extruders may be prohibitive.
U.S. Pat. No. 4,966,542 to Kobayashi discloses apparatus for the formation of a shaped food product wherein two pairs of cutters are used to reduce production loss caused by scattering of cut food by centrifugal force. Each cutter rotates about its own axis and revolves orbitally. According to the Kobayashi patent, even if the cutters make their serf rotation and orbital revolution at high speed, it does not cause scattering of food material, therefore making high speed production possible. However, the apparatus of U.S. Pat. No. 4,966,542 does not partially cut the extrudate to obtain three-dimensional shaped products.
U.S. Pat. No. 4,920,572 to Repholz et al discloses a multi-orifice coextrusion method and apparatus for preparing dual-textured pet food. The multi-orifice coextruding apparatus comprises a slicing means which functions to slice the center-filled stream as it is discharged from the die passages. A preferred slicing means is a rotating knife assembly which comprises about six to eight knives which are mounted on a hub which, in turn is mounted on a shaft disposed at about the center point of the die. According to Repholz et al the apparatus advantageously comprises a hood or cage-type element to prevent product which is sliced from the center-filled stream at high rates from being thrown in undesirable directions by the action of the rotating knife assembly. However, the Repholz et al patent does not disclose the production of partially cut extrudate pieces.
Multi-orifice extruders are also known in the pretzel extrusion art. However, like the Repholz et al apparatus and method, known pretzel extruders do not provide for partial cutting of the extrudate to obtain three-dimensional pieces.
The present invention provides a method and apparatus for the mass production of three dimensional food products, such as crackers, glassy half-products, puffed or fully expanded snacks, ready-to-eat cereals, confections, and pet foods in four-legged standable animal or other shapes. The three-dimensional food products are produced using one or more multi-orifice extruders to increase production rates while reducing cutter speeds to prevent undesirable scattering and deformation of the pieces.